It is known that polybutadiene and polyisoprene, butadiene/isoprene block copolymers and random butadiene/isoprene copolymers can be selectively hydrogenated using so-called coordination catalysts. In this context, reference is made to “Journal of Polymer Science”, Part A/1, Vol. 9, 2617–2623 (1971). There, it is reported, inter alia, that random copolymers of butadiene and isoprene can be selectively hydrogenated using certain coordination catalysts comprising transition metal salts of 2-ethylhexanoic acid and organoaluminum compounds. In the case of butadiene/isoprene block copolymers, the polybutadiene block is preferably hydrogenated. In this publication, no product properties or physical parameters of the hydrogenated products are described, nor any information given regarding the structure of the polymers. There are also no indications of any technical properties of the products which make them appear suitable for certain intended uses.